I can abstain you can abstain he can abstain we can abstain you can abstain they can abstain
V-ing form
I can be abstaining you can be abstaining he can be abstaining we can be abstaining you can be abstaining they can be abstaining
Perfect
I can have abstained you can have abstained he can have abstained we can have abstained you can have abstained they can have abstained
V-ing perfect
I can have been abstaining you can have been abstaining he can have been abstaining we can have been abstaining you can have been abstaining they can have been abstaining
Negation
Simple form
I can't abstain you can't abstain he can't abstain we can't abstain you can't abstain they can't abstain
V-ing form
I can't be abstaining you can't be abstaining he can't be abstaining we can't be abstaining you can't be abstaining they can't be abstaining
Perfect
I can't have abstained you can't have abstained he can't have abstained we can't have abstained you can't have abstained they can't have abstained
V-ing perfect
I can't have been abstaining you can't have been abstaining he can't have been abstaining we can't have been abstaining you can't have been abstaining they can't have been abstaining
Interrogative form
Simple form
can I abstain? can you abstain? can he abstain? can we abstain? can you abstain? can they abstain?
V-ing form
can I be abstaining? can you be abstaining? can he be abstaining? can we be abstaining? can you be abstaining? can they be abstaining?
Perfect
can I have abstained? can you have abstained? can he have abstained? can we have abstained? can you have abstained? can they have abstained?
V-ing perfect
can I have been abstaining? can you have been abstaining? can he have been abstaining? can we have been abstaining? can you have been abstaining? can they have been abstaining?
Interro-negative form
Simple form
can't I abstain? can't you abstain? can't he abstain? can't we abstain? can't you abstain? can't they abstain?
V-ing form
can't I be abstaining? can't you be abstaining? can't he be abstaining? can't we be abstaining? can't you be abstaining? can't they be abstaining?
Perfect
can't I have abstained? can't you have abstained? can't he have abstained? can't we have abstained? can't you have abstained? can't they have abstained?
V-ing perfect
can't I have been abstaining? can't you have been abstaining? can't he have been abstaining? can't we have been abstaining? can't you have been abstaining? can't they have been abstaining?